We rarely stop to think about the speed at which the Earth rotates, unless we’ve had a particularly slow or fast day.
But the rotation of the Earth actually dictates a lot about our planet, including how much Sun we’re exposed to, how long the nights are, and even the wind. So, what’s the rotation like on other planets?
Jupiter is the fastest spinning planet in our solar system, while Venus moves the slowest. The rotation determines how long a day is on the surface. On Jupiter, a day would fly by, while things on Venus go a lot slower.
All planets in our solar system are spinning, and most of them spin in the same direction (Venus and Uranus are the odd ones out).
From the fast spinning to the slow moving, our solar system is made up of a series of fascinating planets. Read on to discover more about the speed our neighbor planets move through space.
Which Planet Spins The Fastest?
Gas giant Jupiter is the fastest spinning planet within our solar system. Jupiter spins so quickly that it takes only ten hours for its equator to complete one full rotation. The planet is spinning at a speed of roughly 28,000 miles per hour.
That means that if you were standing on Jupiter’s equator, you’d see the Sun rise in the east, then set in the west, before we’ve had even half a day on Earth.
But Jupiter doesn’t spin at quite the same speed across the planet. Jupiter is a gas planet, mostly made of hydrogen and helium. Without a solid body, the atmosphere at the top of the planet moves slightly slower than the atmosphere at the equator.
Across the equator, from distances 10 degrees North to 10 degrees South, Jupiter’s rotation period is 9 hours, 50 minutes, and 30 seconds. The areas either side of these latitudes spin every 9 hours, 55 minutes, and 40.6 seconds.
The official rotation period of Jupiter is something different again. This measures the rotation of Jupiter’s magnetosphere, a cavity in the solar wind caused by the magnetic field. This has a rotation period of 9 hours, 55 minutes, and 29.7 ± 1 seconds.
So, Jupiter has three recognized rotation periods, but they’re all roughly 10 hours.
The rotation of Jupiter also affects the very shape of the planet. As a gaseous planet, the fast rotation causes a bulge at the equator, large enough to be seen through a telescope. This is caused by those differing rotation speeds.
The days might go fast on Jupiter, but a year moves very slowly. Jupiter orbits the sun once every 11.86 years. It also doesn’t experience seasons the way that we do. As the axial tilt of Jupiter is small, the changes in season are negligible.
What Is The Slowest Spinning Planet?
Venus is the slowest rotating planet in our solar system. It takes Venus an incredible 243 days to complete a single rotation, traveling at a speed of 4.05 miles per hour. In comparison, the Earth rotates at over 1000 miles per hour.
Venus spins so slowly, that one single day lasts longer than a year. It takes Venus, the second-closest planet to the sun, only 224.7 Earth days to complete an orbit. By the time a Venus year has passed, it will take 18.3 more Earth days before a day on Venus has gone by.
Venus is also pretty unusual in its direction of rotation. Most planets rotate counterclockwise when viewed from above. But Venus spins clockwise.
Planets spin because when the dust clouds and gasses that formed our solar system collapsed, the force pulled everything into a spinning disc. It’s thought that Venus (and Uranus, the other clockwise rotating planet in our solar system) might have been knocked in the other direction by asteroids.
This was a lot more common in the early days of the Solar System, where everything was more chaotic.
A small planet with a dense atmosphere, it’s thought that the slow rotation of Venus might be partly caused by its proximity to the sun.
Gravitational pull can lead to tidal locking, where the rotational spin of a smaller orbiting body is equal to the orbiting period. While Venus isn’t tidal locked to the Sun, it could be experiencing a similar effect.
Do All The Planets Spin?
All the planets in our solar system are currently spinning, although they do so at very different speeds. While Jupiter rotates at roughly 28,000 miles per hour, Venus only spins at 4.05 miles per hour.
It’s possible that some exoplanets don’t spin, but it seems unlikely. Planets are formed by masses of particles coming together, and attracting other particles.
As they’re drawn together, they pull creates a faster rotation, and the planet will continue this spin. The only reason a planet would stop spinning would be if it was hit by another object in just the right way.
Rogue planets are planets without stars, but these too probably have a rotation. This is for a similar reason. Planets are formed with rotation, and with nothing to stop it, they keep spinning.
Does Mercury Spin?
Due to its proximity to the Sun, Mercury has a slow, tidal-locked spin. It has a 3:2 spin-orbit resonance, meaning for every two years on Mercury, three days have passed. A day on Mercury lasts for 58.7 Earth days. A year, however, takes 87.87 Earth days.
Because of the 3:2 spin-orbit resonance, different hemispheres do face the Sun. In a 1:1 spin-orbit resonance, the matching rotations mean only one side ever faces toward the planet.
This is why we only ever see one side of the moon. The Earth and moon are tidal locked in a 1:1 spin-orbit resonance.
Will The Earth Ever Stop Spinning?
The rotation of the Earth is gradually slowing, and it has been doing so for a long time. Scientists think that this is due to the gravitational influence of the moon.
Over millions of years, the Moon pulls on the Earth as it gradually moves away. The result of this gravitational pull is thought to be an increase to the day by about 1.8 milliseconds every single century. Not enough for any human being to notice.
However, this won’t cause the Earth to ever stop spinning, because the angular momentum that causes the spin won’t stop.
The only way for the Earth to stop would be for another object to collide in an exact way that puts a halt to angular momentum.
The chances of this happening are incredibly unlikely. If the Earth were to stop spinning, the result would be a massive change to the climate.
All the planets in our solar system are spinning, although they do so at very different rates. While fast-moving Jupiter speeds across its orbit, Venus moves so slowly you’d hardly notice a day has gone by.
The speed at which a planet spins is influenced by a number of factors, and the direction in which planets spin was set by the formation of the solar system itself!
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